1. Field of the Invention
The present invention generally pertains to the adjustment of the orientation (namely the aiming direction) of the beams emitted by headlights, notably motor vehicles. It more particularly concerns an improved device for the heightwise and widthwise adjustment of the aiming direction of the reflector of such headlights or of the whole headlight assembly.
2. Description of the Prior Art
There already is a known prior art adjusting device in which the reflector is supported, at the rear, on the casing, by means of three bearing points which define the three apexes of a right-angled triangle. The supporting point, corresponding to the right angle of the triangle, is fixed while the other two points are adjustable and respectively enable the heightwise and widthwise adjustment of the aiming direction of the reflector and the light, so that the beam is suitably aligned with respect to the axis of the road.
However, to be able to use a device such as this conveniently and, notably, to be able to do the heightwise adjustment, which is done at the lowest supporting point, from the top of the headlight, it is necessary to provide for an inconvenient and bulky bevel gear system.
In more sophisticated systems of this kind, it is further known to adjust the lower supporting point which determines the heightwise changing of the beam, no longer by a screw or the like but by a small two-way electrical motor controlled by the driver from his seat inside the vehicle. In this case, the widthwise adjustment screw is maintained, so that the adjustment of the aiming direction combines in this case a manual adjustment of the lateral direction, for example by means of a screwdriver, and a heightwise adjustment through a suitable control of the motor.
Thus, in these known devices, only the heightwise setting or pre-setting can be done by modern automated methods that bring into play an automatic control of the movement of the reflector as a function of appropriate photometric measurements, while the directional adjustment still has to be done by hand.
It would however be desirable to be able to use the driving member to perform both types of adjustment. However, in the existing configuration, it would then be necessary to provide firstly mechanical switch-over means selectively assigning the output of the driving organ to either of the two adjustable supporting points and secondly a linkage enabling transmission of the effort required for the adjustment up to the second bearing point which is diagonally opposite the first one. It will be understood that a system of this type would not only increase the complexity of the drive assembly to a considerable extent, but would further cause a substantial increase in the space occupied by the headlight assembly.
Finally, a device is known from the U.S. Pat. No. 4,333,131, wherein the two adjustable bearing points are located on the same lateral side of the headlight. However, here again, there is provision for two distinct driving members (two screws) to determine the two adjustment modes manually.